Steroid Resistance/Dependence Might Be an Alarming Feature for Cytomegalovirus Infection Among Ulcerative Colitis Patients With Increased Disease Activity.

Background/Aims This study aimed to determine the prevalence of cytomegalovirus (CMV) infection among patients with moderate to severe active ulcerative colitis (UC) and to determine the risk factors for CMV infection according to the demographic features of these patients. Patients/Methods A total of 183 patients with severe or moderate active UC were enrolled in the study after retrospective analysis. The disease severity of UC was determined according to the Mayo Score. CMV infection was investigated by real-time quantitative polymerase chain reaction (PCR) and the immunohistochemical (IHC) staining method in colonic mucosal biopsies. Results CMV infection was diagnosed in 33.9% of patients with UC. UC patients diagnosed with CMV infection had significantly higher Mayo Score levels (9.68 vs 8.56 and p=0.001). The long-term presence of UC disease, steroid, azathioprine (AZA), and anti-tumor necrosis factor-alpha (anti-TNF-alpha) usage increased the risk of CMV infection (p=0.001 and odds ratio=1.168; p=0.001 and odds ratio=2.967; p=0.004 and odds ratio=2.953; p=0.003 and odds ratio=3.861, respectively). CMV infection increases the risk of developing steroid resistance or dependency (p=0.002 and odds ratio=3.147; p=0.002 and odds ratio=5.085, respectively). Post-treatment clinical remission and mucosal healing rates were higher in CMV-negative patients than in CMV-positive patients (99.2% vs 91.9%, p=0.018 and 86.8% vs 70.9%, p=0.015). A higher rate of need for colectomy had been found in patients with CMV infection (5 patients vs 1 patient; p=0.034 and odds ratio=10.526). Conclusions The presence of CMV infection increases the severity of the disease and worsens clinical outcomes, leading to adverse treatment outcomes. CMV infection increases the requirement for colectomy. The presence of steroids, immunosuppressives such as AZA, and anti-TNF-alpha usage increases the occurrence of CMV infection. CMV infection should be suspected in patients with moderate to severe UC activity.

Ancient Schwannoma as an exceptional thoracic spinal tumor: A case report.

Schwannomas are mostly benign tumors arising from the nerve sheath. These tumors can be found anywhere in the body. Depending on their locations, they may cause compressive symptoms as well as cosmetic or functional defects. Ancient schwannomas, the rare variant of schwannomas, are the slow-growing tumors characterized with cystic necrotic degeneration areas in the neoplastic tissue. Ancient schwannomas rarely occur in the spinal canal, they are particularly unusual in the thoracic spine. Herein we present a 66-year-old woman with chronic back pain who is detected a cystic mass in her thoracic spine by magnetic resonance imaging and is diagnosed with ancient schwannoma by histological examination.

Predicting pathological response and overall survival in locally advanced gastric cancer patients undergoing neoadjuvant chemotherapy: the role of PET/computed tomography.

BACKGROUND: Gastric cancer is the second leading cause of cancer-related deaths, with a 5-year survival rate of about 20-25%. The ability to predict pathological response (PR) to neoadjuvant chemotherapy (NACT); hence, overall survival (OS) probability of patients can allow the clinician to individualize treatment strategies. We investigated the role of F-18 fluorodeoxyglucose PET-computed tomography (F-18 FDG PET/CT) in predicting histopathologic response and prognosis in locally advanced gastric cancer (LAGC) patients undergoing NACT. METHODS: F-18FDG PET/CT images taken before and after NACT, adenocarcinoma histopathology and operation pyesis reports of 43 LAGC patients were analyzed. Maximum (SUVmax) and mean (SUVmean) standardized uptake values, metabolic tumor volume (MTV), and total lesion glycolysis (TLG) of lesions were measured before and after NACT. Changes in percentage were calculated for ΔSUVmax%, ΔSUVmean%, ΔMTV%, ΔTLG%, and cutoff values were determined by receiver operating characteristic curve analysis. NACT response in pathology pyesis was determined according to the College of American Pathologists classification. PR and OS were analyzed with Kaplan-Meier and Cox proportional hazards regression models based on cutoffs found with PET measurements. RESULTS: Cutoffs were ΔSUVmax = 33.31%, ΔSUVmean = 42.96%, ΔMTV = 30.38%, and ΔTLG = 28.14%, and all patients showed significance in PR and OS based on these cutoffs (all P < 0.01). PET/CT findings before and after NACT (ΔMTV > 30.38%, ΔTLG > 28.14%) predicted PR with 100% sensitivity and specificity. Multivariate analysis showed ΔSUVmean as an independent risk factor predicting OS (hazard ratio 0.348, 95% confidence interval 2.91-22.3, P = 0.03). CONCLUSIONS: Metabolic parameters obtained with F-18 FDG PET/CT scanning before and after NACT in LAGC patients can accurately predict PR and OS.

Coexistence of low-grade mucinous neoplasm and carcinoid (collision tumor) within multiple appendiceal diverticula: A case report.

Neoplasms of the appendix are very rare. They usually show glandular or neuroendocrine differentiation, and when they both occur in the same area, it is called a "collision tumor." Low-grade mucinous neoplasms associated with appendiceal diverticula are also uncommon. The appendectomy specimen of a 60-year-old man contained dense and mucoid luminal content on the distal tip, and similarly a solid, yellow, lumen-obscuring tumor with a diameter of 1.5 cm at the base of the appendix was detected. Microscopically, there were three diverticula that comprised herniation of the mucosal layer through the appendiceal wall. Interestingly, all of the diverticula and the normal-appearing appendiceal wall were lined by adenomatous epithelium. The luminal portion had pools of mucin-containing, rare clusters of low-grade epithelium that gave rise to the diagnosis of a "low-grade mucinous neoplasm." The solid-appearing tumor was diagnosed as a "neuroendocrine neoplasm," and there was no transition zone between these two types of tumors. There are some cases that have been reported as low-grade mucinous neoplasms associated with appendicular diverticula and collision tumors consisting both mucinous neoplasms and carcinoid tumors in the literature; our case has a unique appearance with two different types of tumors both in the appendix wall and within multiple diverticula.

Analysis of clinical and histopathological findings in Russell body gastritis and duodenitis.

INTRODUCTION: Russell body gastritis is considered as a rare, benign, incidental finding characterized by dense accumulation of plasma cells containing Russell bodies in the lamina propria. In this study, clinical and histopathological features of 12 cases of Russell body gastritis/duodenitis were presented. MATERIALS AND METHODS: Clinical data, histopathological findings including Helicobacter pylori infection, Sydney system classification, Russell body density and immunohistochemical findings were evaluated in 11 gastric and 1 duodenal mucosal biopsy from 11 patients. RESULTS: Six cases were male, 5 were female and the mean age was 72 (44-87). The most common site was antrum (10/12), one case was located in cardia and one in heterotopic gastric mucosa of duodenal bulb. H. pylori was detected in half of the cases. One of the cases was accompanied by gastric tubular adenoma, one by gastric well-differentiated adenocarcinoma and one by plasma cell neoplasm. In all cases, globules were positive with PAS stain. CONCLUSION: Russell body gastritis must be kept in mind while reporting endoscopic biopsies because this entity may be misdiagnosed as signet ring carcinoma and may be associated with neoplasms. Absence of nuclear atypia, mucin stains, cytokeratins, plasma cell and hematolymphoid antigen markers are useful in differential diagnosis. Associated H. pylori infection, as well as rarely carcinomas, adenomas and plasma cell neoplasms, may be observed.

Approach to primary thyroid lymphoma: case series.

Primary thyroid lymphomas are rare thyroid neoplasms. Mucosa Associated Lymphoid tissue (MALT) lymphoma and diffuse large B-cell Non-Hodgkin lymphoma are the most common types. It is more common in the elderly, and especially in women. Patients usually present with a rapidly growing mass in the neck. This article aimed to present the epidemiological features, treatment and prognostic factors of thyroid lymphomas by retrospectively reviewing 4 patients with thyroid lymphoma. Four patients were treated for primary thyroid lymphoma, two of whom were women and two were men, with a mean age of 63.7 (51-74) years. Common complaint of those patients was the sudden swelling of the neck. Two patients were diagnosed with fine needle aspiration biopsy (FNAB) and the other two patients were diagnosed with surgical excision. Chemotherapy and radiotherapy were applied to all four patients. While one patient died in the second year of follow-up, the other three patients are still being followed. Primary thyroid lymphomas are not aggressive tumors, and the most effective treatment is radiotherapy.

Coexistence of low-grade mucinous neoplasm and carcinoid (collision tumor) within multiple appendiceal diverticula: A case report.

Neoplasms of the appendix are very rare. They usually show glandular or neuroendocrine differentiation, and when they both occur in the same area, it is called a "collision tumor." Low-grade mucinous neoplasms associated with appendiceal diverticula are also uncommon. The appendectomy specimen of a 60-year-old man contained dense and mucoid luminal content on the distal tip, and similarly a solid, yellow, lumen-obscuring tumor with a diameter of 1.5 cm at the base of the appendix was detected. Microscopically, there were three diverticula that comprised herniation of the mucosal layer through the appendiceal wall. Interestingly, all of the diverticula and the normal-appearing appendiceal wall were lined by adenomatous epithelium. The luminal portion had pools of mucin-containing, rare clusters of low-grade epithelium that gave rise to the diagnosis of a "low-grade mucinous neoplasm." The solid-appearing tumor was diagnosed as a "neuroendocrine neoplasm," and there was no transition zone between these two types of tumors. There are some cases that have been reported as low-grade mucinous neoplasms associated with appendicular diverticula and collision tumors consisting both mucinous neoplasms and carcinoid tumors in the literature; our case has a unique appearance with two different types of tumors both in the appendix wall and within multiple diverticula.

Arteriography and Histopathology of Vascular Beds in Traumatically Amputated Fingers.

BACKGROUND: The success of replantation following traumatic amputation is determined by the quality of the vascular anastomoses. The purpose of this study was to assess the vascularity of injured arteries from traumatically amputated digits using arteriographic and histopathological analysis. METHODS: 25 amputated digits were included in the study. Crush and avulsion injuries were evaluated according to the Venkatramani classification. The amputated arteries were dissected under a microscope, and the arterial route determined with a transducer. Arteriography using fluoroscopy was evaluated by a radiologist. The area thought to be damaged was dissected and 2-mm slices taken for histopathological examination, and scored using the parameters of fibrin accumulation, oedema, separation, and bleeding. RESULTS: Arterial flow was observed in 6 of 7 in the avulsion group. In the crush group, arterial flow was observed in 11 of 16 cases. On histopathological examination in all cases there were 2 or more findings of either oedema, fibrin formation, bleeding or hernia. These findings were more common in the crush group then the avulsion group. CONCLUSIONS: The intravascular introduction of radio contrast agents to amputated digit prior to replantation may give further information particularly in avulsion amputations.

Giant pancreatic solid cystic desmoid tumor with two ectopic adrenal tissues.

A 19-year-old woman presented with painless swelling of the abdomen. During surgery, a giant mass measuring 37 cm×26 cm×12 cm within the distal pancreas invading the spleen was noted. The clinical diagnosis of a solid cystic pseudopapillary tumor of the pancreas was suspected. Distal pancreatectomy, splenectomy, and debulking surgery were performed. Histological examination showed that the tumor infiltrated the spleen and pancreatic parenchyma, and sections of the solid areas revealed a proliferation of spindle-shaped or stellate cells growing in fascicular and storiform patterns within a myxoid intercellular matrix. Cystic areas were representing the entrapped excretory pancreatic ductules. Interestingly, there were two ectopic adrenal tissues found incidentally in the peripheral portion of the tumor. The histopathologic and immunohistochemical features were consistent with a solid cystic desmoid tumor of the pancreas. Desmoid tumors of the pancreas are very rare, and if they present as a solid cystic lesion, their diagnosis may be difficult. We report the case for its rarity and huge size and to emphasize a regular follow-up because the long-term prognosis is currently unknown.

DNA methylation profiling identifies novel markers of progression in hepatitis B-related chronic liver disease.

BACKGROUND: Chronic hepatitis B infection is characterized by hepatic immune and inflammatory response with considerable variation in the rates of progression to cirrhosis. Genetic variants and environmental cues influence predisposition to the development of chronic liver disease; however, it remains unknown if aberrant DNA methylation is associated with fibrosis progression in chronic hepatitis B. RESULTS: To identify epigenetic marks associated with inflammatory and fibrotic processes of the hepatitis B-induced chronic liver disease, we carried out hepatic genome-wide methylation profiling using Illumina Infinium BeadArrays comparing mild and severe fibrotic disease in a discovery cohort of 29 patients. We obtained 310 differentially methylated regions and selected four loci comprising three genes from the top differentially methylated regions: hypermethylation of HOXA2 and HDAC4 along with hypomethylation of PPP1R18 were significantly linked to severe fibrosis. We replicated the prominent methylation marks in an independent cohort of 102 patients by bisulfite modification and pyrosequencing. The timing and causal relationship of epigenetic modifications with disease severity was further investigated using a cohort of patients with serial biopsies. CONCLUSIONS: Our findings suggest a linkage of widespread epigenetic dysregulation with disease progression in chronic hepatitis B infection. CpG methylation at novel genes sheds light on new molecular pathways, which can be potentially exploited as a biomarker or targeted to attenuate inflammation and fibrosis.

Significance of IMP3, nucleophosmin, and Ki-67 expression in papillary thyroid carcinoma.

The purpose of our study was to investigate the diagnostic value of expression of IMP3, nucleophosmin, and correlation of these markers with Ki-67 proliferation index in papillary thyroid carcinoma and benign neoplasms of thyroid gland. The aim was also to investigate whether there is a difference between papillary and micropapillary carcinomas with regard to clinicopathologic parameters beside IMP3, nucleophosmin, and Ki-67 proliferation index. It was concluded that IMP3 and nucleophosmin cannot be a routine diagnostic marker for discrimination of papillary carcinomas and benign lesions. IMP3 positive staining was quite scarce in IMP3 positive papillary carcinomas although specifity of IMP3 is 100%. A statistically significant correlation was not detected between nucleophosmin, IMP-3, and Ki-67 proliferation index. A statistically significant correlation was found between tumor size, lymphovascular embolism, and Ki-67 proliferation index. There was also significant correlation between tumor size and lymphovascular embolism.

The effect of diclofenac on matrix metalloproteinase levels in the rotator cuff.

INTRODUCTION: Matrix metalloproteinases (MMPs) are involved in physiological events such as restructuring of the tissue, morphogenesis, wound healing and normal developmental process. Use of diclofenac sodium following rotator cuff repair can disrupt healing of tendon through acting on MMPs. MATERIALS AND METHODS: Supraspinatus tendons of rats (n = 84) were detached from their insertion on humerus, and repaired to anatomic footprint. Rats were divided into study group (n = 42) and control group (n = 42). Study group received a dose of 1 mg/kg daily diclofenac sodium subcutaneously. The rats were killed at weeks 1, 3 and 6, and seven rats from each groups were included in biomechanical and immunohistological examinations. Immunohistological staining of MMP-2, MMP-3 and MMP13 were used. RESULTS: Maximum load was reduced in the study group at the end of week 1 (8.76 vs. 5.28 N) (p = 0.01). MMP-3 level was statistically significantly lower in the study group at the end of week 1. MMP-13 level and stiffness decreased towards week 6 in the study group while in the control group the level of MMP-2 decreased towards week 6. CONCLUSION: Diclofenac has an impact on the levels of MMP-2, MMP-3 and MMP-13, which are needed for normal healing process, and it can also lead to disruption of tendon healing.

Gnathic osteosarcomas, experience of four institutions from Turkey.

Osteosarcoma is the most frequent primary gnathic sarcoma. Neither the etiology nor the variables effecting the prognosis are fully known due mostly to the rarity of gnathic osteosarcomas. To date a considerable number of clinicopathologic features have been suggested in the evaluation of gnathic osteosarcomas. Still there is a need to experience on several aspects of management. The aim of this study is to report a series of 33 cases of osteosarcoma involving either mandible or maxilla. The clinical, radiological and histopathological features of our cases have usually been non-specific and the most frequent provisional diagnosis were "benign fibroosseous lesion, abnormal mass, giant cell granuloma and benign bone tumor". This non-specific presentation of osteosarcomas of the jaws is compatible with those reported previously. A combined clinical, radiological and pathological study is essential in arriving at the correct diagnosis.

Histomorphological comparison of immobilization and denervation atrophies.

OBJECTIVE: The aim of this study was to compare the histomorphological changes in the muscle tissue after immobilization and denervation atrophies in an animal model. METHODS: The study included 30 Ross-800 hybrid chickens (60 legs) divided into two study (immobilization and denervation) and two control groups. The knee and ankle joints were fixed with a Kirschner wire in the immobilization atrophy group and sciatic nerve resection was performed in the denervation group. The unaffected side of each group was used as controls. The weight, volume, height, diameter and the rate of elongation of the Achilles tendons, and the amount of fat deposition, degeneration and fibrosis were compared between the two groups at the end of 3 weeks. Hematoxylin-eosin staining was performed for a histopathological assessment of the muscles. The Mann-Whitney U-test was used for comparisons. RESULTS: Loss of the volume, weight and muscle length was significantly lower in the denervation group than the immobilization group (p<0.05). Differences between the diameter of the Achilles tendon and length and diameter of the short heads were not statistically significant. There were statistically significant differences in fat deposition, degeneration and fibrosis between the degeneration group and the immobilization group (p<0.05). Pixel counting revealed a significant difference in the number of pixels in the fatty tissue area (white area) between the denervation group and the immobilization group (p<0.05). CONCLUSION: Our results showed that histomorphological changes were more in the denervation group than the immobilization group in an experimental chicken model.

Lack of correlations among histopathological parameters, Ki-67 proliferation index and prognosis in pheochromocytoma patients.

BACKGROUND: In this study prognostic correlations of histopathologic parameters and the Ki-67 proliferation index and as well as the diagnostic value of immunohistochemical markers in pheochromocytomas were evaluated. MATERIALS AND METHODS: A total of 22 patients diagnosed with a pheochromocytoma between 2000-2010 in Izmir Katip Celebi University Ataturk Training and Research Hospital were included. Diagnostic value of the PASS scoring system, and prognostic correlations of histopathologic parameters and Ki-67 proliferation index were investigated. SPSS for Windows 17.0 software was used for statistical analysis. RESULTS: There was no statistically significant correlation between recurrence and clinicopathologic parameters or the PASS score (PASS>4). In addition, there were no statistically significant correlations between PASS score and clinicopathologic parameters, such as diameter (5 cm), weight (>100g), gender (female/male ratio) and age (25-45/45-55/>55). Besides, there were no significant correlation between diameter and clinicopathological parameters and also recurrence. However, there was a statistically significant correlation between Ki-67 proliferation index and capsule invasion (p=0.047). CONCLUSIONS: Some but not most of the findings in our study were concordant with the literature. To clarify relationships, investigations with standard scoring systems which are not affected by subjective factors and feature appropriate histopathological criteria should be made on larger study groups.

Effects of mucosal TNF-alpha levels on treatment response in Crohn's disease patients receiving anti-TNF treatment.

BACKGROUND/AIMS: We aimed to find out if mucosal TNF-α (m-TNF-α) levels have predictive impact on anti-TNF treatment response in Crohn's disease (CD). METHODOLOGY: TNF-alpha values were determined with immunohistochemical staining of intestinal biopsies taken from 35 subjects on anti-TNF treatment for CD and 25 controls. Correlation between m-TNF-α levels and anti-TNF treatment were evaluated. RESULTS: m-TNF-α levels were determined higher in CD group (28.0±8.9 vs 5.8±2.1; P<0.001). m-TNF-α levels were lower in CD patients who were hospitalized (23.0±8.7 vs. 30.3±8.1; P=0.024). Although not to a statistically significant level, favorable parameters such as clinical remission (28.5±8.0 vs. 26.4±11.8, p=0.419) and mucosal healing (29.9±8.2 vs. 23.9±9.2, p=0.097) were increased in patients with high m-TNF-α levels whereas unfavorable parameters such as relapse (26.0±9.4 vs. 29.7±8.2, P=0.107), surgery requirement (22.8±11.1 vs. 29.1±8.1, P=0.147), steroid requirement (25.9±9.0 vs. 28.6±8.9, P=0.595), and anti-TNF intensification (22.3±3.8 vs. 28.5±9.0, P=0.183) were increased in patients with low m-TNF-α levels. CONCLUSIONS: High mucosal TNF-α levels before treatment have favorable effects on anti-TNF treatment response in CD. Presence of high m-TNF-α levels at the diagnosis may be encouraging in early initiation of anti-TNF treatment.

The effects of hematological parameters and tumor-infiltrating lymphocytes on prognosis in patients with gastric cancer.

BACKGROUND: It is well known that tumor-infiltrating lymphocytes (TIL) and, to a lesser extent, peripheral hematologic parameters from patients with cancer have to effect on prognosis. The aim of this study was to evaluate the effect of hematologic parameters and TIL on prognosis of patients with gastric cancer. METHODS: 236 patients who had diagnosed as gastric adenocarcinoma. All hematologic parameters were noted at the time of diagnosis. The number of lymphocyte aggregates as well as the number of lymphocytes within these agregat was counted.The prognostic significance and correlations of high neutrophil-lymphocyte ratio (NLR) together with TIL, was evaluated by multivaried analysis. RESULTS: The cut-off values of NLR and derived NLR (dNLR) were 3.8 and 2. The NLR was independently associated with survival (P < 0.001). dNLR was not independently associated with overall survival. No significant advantages for overall survival were found for the high TIL (p: 0.372). It was not determined correlation between TIL - NLR and TIL-lymphoid aggregate density (respectivly, P: 0.104; P: 0.246). CONCLUSIONS: The results suggest that the elevated NLR predicts poor overall survival following at the time diagnosis for all stage gastric cancer. dNLR was not independently associated with overall survival. There is insufficient evidence to the assesment of TIL by a nonspesific method. Therefore further studies is required, to confirm our hypothesis in larger patient cohorts.

Oral epithelial barrier function and the role of nuclear factor kappa-ß pathway in the pathogenesis of aphthous ulceration.

BACKGROUND/AIMS: The normal oral mucosa is usually tolerant to its special microenvironment. Epithelial integrity and a wellmanaged immune system are important in sustaining harmony. A close look at the role played by adaptive immunity during recurrent aphthous ulcerations may throw some light into the pathogenesis. MATERIALS AND METHODS: In this report, we provide a concise review of oral epithelial barrier function and present data on the possible pathogenetic mechanism of aphthous ulceration using immunohistocemical signs of nuclear factor kappa beta pathway activation on fourteen cases of mucosal aphthous ulcerations. RESULTS: We strongly support the hypothesis that oral aphthous ulcerations develop as a result of loss of epithelial barrier function and that nuclear factor kappa beta signaling pathway seems to be involved in this type of injury. CONCLUSION: Interventions that strengthen the mucosal barrier function or modulate inappropriate activation of nuclear factor kappa beta signaling pathway can be considered in the treatment of oral aphthous ulcerations.

Extensive fibrin accumulation and accompanying epithelial changes in the pathogenesis of ligneous mucosal disease (ligneous periodontitis).

Certain abnormal products of human tissues are resistant to degradation. The fibrillary ultrastructure of some of these are seen integrated with normal tissue components. The accumulations seen in colloid milium, lichen, and macular amyloidosis are of this type. Apoptosis of keratinocytes and filamentous degeneration of some proteins can be important in the pathogenesis. A similar pathogenetic mechanism is possible in ligneous mucosal disease, which is a rare disorder of plasminogen deficiency characterized by amyloid-like amorphous accumulations. Gingival and conjunctival mucosal pseudomembraneous masses are typical and concomitant involvement of other sites are not unusual. The accumulated substance is thought to be an abnormal fibrin degradation product. In this study, we have examined 6 representative samples from 5 gingival and 1 conjunctival lesions displaying characteristic features. Immunohistochemically, fibrinogen was detected as an early change. TUNEL staining revealed numerous apoptotic keratinocytes in this phase as well. These cells also expressed nuclear factor kappa beta. Apoptotic cells showed loss of epithelial cadherin immunostaining. In the later phase, the subepithelial accumulations failed to stain with antifibrinogen, wide spectrum, and high molecular keratins, type 4 collagen and nuclear factor kappa beta. Our findings suggest that the accumulations in ligneous mucosal disorder result from an abnormal healing process and they probably form as a combination of organised fibrinogen, epithelial fragments, and connective tissue matrix.

The cell with a thousand faces: detection of myoepithelial cells and their contributions in the cytological diagnosis of salivary gland tumors.

Myoepithelial cells are an important component of salivary gland tumors and are partly responsible from the diverse histology of them. In this study, we focus on the myoepithelial cell differentiation by using cytological morphology in a various types of salivary gland tumors especially with regard to their contribution to the diagnosis. The relation of myoepithelial cells with stromal matrix and the associated epithelial cells were evaluated. Cytologic slides of one hundred and forty one benign and twenty malignant salivary gland tumors were examined for identification of morphologically different myoepithelial cells such as; spindle-stellate, polygonal-epitheloid, plasmacytoid, basal and clear types. The best examples of myoepithelial cells were detected in pleomorphic adenomas, in some monomorphic adenomas and in the adenoid cystic carcinoma cases. Most of the pleomorphic adenomas were composed more than one type of myoepithelial cells and epitheloid-spindle cell combination was frequent. Basal and clear cell types of myoepithelial cells closely resembled the epithelial cells and their identification was relatively difficult. Identification of myoepithelial cell types was easier when they were associated with stromal matrix material and stood as a secondary layer around tubule-forming epithelial cells. Myoepithelial cell components of various salivary gland tumors may be quite different and identification of myoepithelial cell types may pose difficulties. A confident cytologic identification of myoepithelial cells may be critical part of diagnosing salivary gland tumors.